Benign tumour of the kidney, accounting for 5-10% of the neoplasm and thought to arise from the intercalated cells of the collecting ducts.
Has a characteristic mahogany cut-surface with a stellate scar. Radiologically, it can be hard to distinguish from renal cell carcinoma.
Shows typical oncocytic cells with finely granular eosinphilic cytoplasm.
- Nuclei are round with smooth contours and even chromatin
- Nucleoli can be prominent.
- Fine delicate fibrotic bands
- Nearest differential can be eosinophilic variant of renal cell carcinoma, or the chromophobe variant of renal cell carcinoma (rarely, in Birt-Hogg-Dube syndrome, there can be hybrid tumours)